A5013629206- Magnetic properties of thin films
- Theoretical and Computational Physics
- Physics of Superconductivity and Magnetism
- Topological Materials and Phenomena
- Quantum and electron transport phenomena
- 2D Materials and Applications
- Magnetic Properties and Applications
- Magnetic and transport properties of perovskites and related materials
- nanoparticles nucleation surface interactions
- Mechanical and Optical Resonators
- Perovskite Materials and Applications
- Phase-change materials and chalcogenides
- Additive Manufacturing Materials and Processes
- Advanced Memory and Neural Computing
- Quantum Computing Algorithms and Architecture
- Nanoporous metals and alloys
- Advanced Thermodynamics and Statistical Mechanics
- Magnetic Properties of Alloys
- Semiconductor Lasers and Optical Devices
- Adhesion, Friction, and Surface Interactions
University of York
2019-2025
University of Edinburgh
2021-2023
Two-dimensional (2D) van der Waals magnets provide new opportunities for control of magnetism at the nanometre scale via mechanisms such as strain, voltage and photovoltaic effect. Ultrafast laser pulses promise fastest most energy efficient means manipulating electron spin can be utilized information storage. However, little is known about how influence spins in 2D magnets. Here we demonstrate laser-induced magnetic domain formation all-optical switching recently discovered ferromagnet...
Layered van der Waals (vdW) magnets can maintain a magnetic order even down to the single-layer regime and hold promise for integrated spintronic devices. While ground state of vdW was extensively studied, key parameters spin dynamics, like Gilbert damping, crucial designing ultra-fast devices, remains largely unexplored. Despite recent studies by optical excitation detection, achieving wave control with microwaves is highly desirable, as modern information technologies predominantly are...
A unified model of molecular and atomistic spin dynamics is presented enabling simulations both in microcanonical canonical ensembles without the necessity additional phenomenological damping. Transfer energy angular momentum between lattice systems achieved by a coupling term representing spin-orbit interaction. The characteristic spectra phonon are analyzed for different strength temperatures. spectral density shows magnon modes together with uncorrelated noise induced to lattice....
Ultrafast laser excitations provide an efficient and low-power consumption alternative since different magnetic properties topological spin states can be triggered manipulated at the femtosecond (fs) regime. However, it is largely unknown whether already used in data information platforms manipulate of recently discovered two-dimensional (2D) van der Waals (vdW) materials. Here we show that ultrashort pulses (30$-$85 fs) not only domains 2D-XY CrCl$_3$ ferromagnets, but also induce formation...
An antiferromagnet emits spin currents when time-reversal symmetry is broken. This typically achieved by applying an external magnetic field below and above the spin-flop transition or optical pumping. In this work we apply pump-THz emission spectroscopy to study picosecond pumping from metallic FeRh as a function of temperature. Intriguingly find that in low-temperature antiferromagnetic phase laser pulse induces large coherent pumping, while not crossing into ferromagnetic phase. With...
An understanding of the damping mechanism in finite-size systems and its dependence on temperature is a critical step development magnetic nanotechnologies. In this work, nanosized materials are modeled via atomistic spin dynamics, parameter being extracted from ferromagnetic resonance (FMR) simulations applied for FePt systems, generally used heat-assisted recording media (HAMR). We find that increases rapidly close to ${T}_{C}$ effect enhanced with decreasing system size, which ascribed...
The anomalous Hall, Nernst and thermal Hall coefficients of Fe$_{3-x}$GeTe$_2$ display several features upon cooling, like a reversal in the signal below $T = 50$ K pointing to topological transition (TT) associated development magnetic spin textures. Since transport variables are related Berry curvature, possible TT might imply deviations from Wiedemann-Franz (WF) law. However, found, within our experimental accuracy, satisfy WF law for magnetic-fields $\mu_0H$ applied along its inter-layer...
Skyrmions are topologically protected nanoscale magnetic structures with a wide range of potential applications. Here we determine the life cycle skyrmions from their creation to intrinsic dynamics and thermal stability eventual thermodynamic demise. Using atomistic simulations Ir/Co/Pt, parameterized ab initio calculations, demonstrate phase transition skyrmion state under application perpendicular field. The created exhibit Brownian particlelike driven by underlying spin fluctuations. At...
Spin-wave resonance measurements were performed in the mixed magnetic phase regime of a Pd-doped FeRh epilayer that appears as first-order ferromagnetic-antiferromagnetic transition takes place. It is seen measured value exchange stiffness suppressed throughout measurement range when compared to expected fully ferromagnetic regime, extracted via independent means Curie point, for only slight changes volume fraction. This behavior attributed influence antiferromagnetic phase: inspired by...
We demonstrate the possibility of field-free, ultrafast creation topologically protected nanoscale magnetic skyrmions in ferromagnets via single-pulse laser excitation, holding promise for next-generation memory and logic devices.
An antiferromagnet emits spin currents when time-reversal symmetry is broken. This typically achieved by applying an external magnetic field below and above the spin-flop transition or optical pumping. In this work we apply pump-THz emission spectroscopy to study picosecond pumping from metallic FeRh as a function of temperature. Intriguingly find that in low-temperature antiferromagnetic phase laser pulse induces large coherent pumping, while not crossing into ferromagnetic phase. With...
Ultrafast switching of magnetic materials has been shown to be predominantly thermally driven, but excess heating limits the energy efficiency this process. By employing atomistic spin-lattice dynamics simulations, we show that efficient coherent magnetization an insulating magnet can triggered by a THz excitation phonons. We find is driven near <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mi>P</a:mi></a:math> point phonon spectrum in conditions where spins typically cannot...
Abstract The discovery of intrinsic magnetism in two-dimensional (2D) van der Waals (vdW) materials has opened the possibility to explore fundamental interactions between light, electron and spins at atomic limit towards novel device architectures\cite{huang2017layer,Gong2017,GuguchiaSciAdv,wahab2021quantum,GuguchiaSantos,Wahab21,CantosPrieto2021,Alliati20,Genome22}. Ultrafast laser excitations provide an efficient low-power consumption alternative since different magnetic features such as...
We explore the helicity-independent light-induced nucleation of skyrmion lattices in ferromagnetic cobalt-based trilayers with perpendicular magnetic anisotropy. Using Atomistic Spin Dynamics simulations, we show that a high temperature excitation followed by magnon drops and their non-equilibrium relaxation, accessed an ultrafast laser specific duration intensity, can lead to generation lattice stable at room temperature. The window, topological density polarity be additionally manipulated...
Advanced magnetic recording paradigms typically use large temperature changes to drive switching which is detrimental device longevity, hence finding non-thermal routes crucial for future applications. By employing atomistic spin-lattice dynamics simulations, we show efficient coherent magnetisation triggered by THz phonon excitation in insulating single species materials. The key ingredient near the $P$-point of spectrum conditions where spins cannot be excited and when manifold $k$ modes...
We investigate the dynamical switching process of Heat Assisted Magnetic Recording (HAMR) by numerical calculations probability using an atomistic model. Calculations show that at elevated write temperature HAMR there is a loss information arising from 'backswitching': thermodynamic phenomenon which comes into play when ratio Zeeman energy to thermal insufficiently large completely stabilise switched direction. consider special case Heated Dot Recording, where reduction can be related bit...
The discovery of magnetism in two-dimensional (2D) van der Waals (vdW) materials presents an unprecedented opportunity to understand the fundamental interactions between light and spins develop novel device architectures. However, little is known about how laser pulses can affect magnetic properties 2D magnets. Here, we demonstrate laser-induced manipulation domains within CrI <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> flakes. By...
Layered van der Waals (vdW) magnets can maintain a magnetic order even down to the single-layer regime and hold promise for integrated spintronic devices. While ground state of vdW was extensively studied, key parameters spin dynamics, like Gilbert damping, crucial designing ultra-fast devices, remains largely unexplored. Despite recent studies by optical excitation detection, achieving wave control with microwaves is highly desirable, as modern information technologies predominantly are...